Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet. It also enables software developers to create new communication tools with built-in privacy features. Tor provides the foundation for a range of applications that allow organizations and individuals to share information over public networks without compromising their privacy.
Whereas, the Tor Browser is software that lets you browse through the internet by using the Tor's network of virtual tunnels. Hence it is a sort Tor client installed on your device which encrypts your data & information through the Tor private networks.